1. Field of the Invention
The present invention is generally related to a connection system for a plurality of marine propulsion devices and, more particularly, to a connection system that provides improved movement for a marine propulsion device coupling arrangement.
2. Description of the Related Art
Those skilled in the art of marine propulsion systems are aware of many different types of connecting bars which tie marine propulsion devices, such as outboard motors, together in a way that coordinates steering between the devices.
U.S. Pat. No. 4,009,678, which issued to North on Mar. 1, 1977, describes a multiple push-pull cable transmission apparatus. A racing boat is powered by a pair of pendent inboard-outboard drive units having inboard steering arms. A pair of push-pull cable units connect a forward located steering wheel unit to the arms. The cable units extend along opposite sides of the boat with the casing fixed at the steering wheel and the core wires secured to the opposite sides of the steering wheel and to the opposite steering arms. A power steering unit coupled to the one steering arm has an input element. The adjacent cable unit has a threaded extension pipe with a fixed coupler connected to the power control input. A core rod is connected to the core and is slidably mounted in the pipe and is pivotally connected to the power steering link to transmit casing reaction forces to the power input. An adjustable rigid linkage includes a tie rod having adjustable ends pivotally connected to the anchor member on the extension pipes.
U.S. Pat. No. 4,731,035, which issued to Wagner on Mar. 15, 1988, describes a steering mechanism for an outboard motor. The steering mechanism has a pair of opposed single acting cylinders maintained in a spaced relationship by a frame member. A pair of brackets enable pivotal connection of the steering mechanism with a mounting bracket of a motor. A piston is received in and extends between the cylinders and carries a lost motion linkage connectable with the tiller arm of the motor to induce steering movement of the motor upon actuation of the piston.
U.S. Pat. No. 4,778,418, which issued to Mondek on Oct. 18, 1988, describes a tie bar for marine propulsion devices. The marine propulsion devices are respectively pivotable about spaced vertical axes for steering and about a common horizontal axis for tilting. The tie bar includes structure for selectively affording axial extension of the tie bar in response to tilting movement of one of the propulsion devices relative to the other of the propulsion devices and for preventing axial extension of the tie bar during normal steering movements.
U.S. Pat. No. 4,836,812, which issued to Griffiths on Jun. 6, 1989, discloses a steering system for an auxiliary marine engine. The steering system includes an auxiliary engine steering cable operably connected to the hydraulic cylinder of the steering system for the primary engine so that linear movement of the hydraulic cylinder results in movement of the steering cable and pivotal steering of the auxiliary engine.
U.S. Pat. No. 5,370,075, which issued to Rodskier on Dec. 6, 1994, describes a twin outboard sterndrive boat propulsion unit, comprising two outboard propeller drives, having anti-cavitation plates, which are coupled to each other via a tie-bar with a wing profile. In the trim position of the sterndrive for low speed, the wing profile has an angle of attack in order to exert a lifting force on the sterndrives under the influence of the water flowing past it.
U.S. Pat. No. 5,505,106, which issued to Herman on Apr. 9, 1996, describes an adjustable tie rod assembly for a motor vehicle. The intermediate and inner rod end sections of the adjustable tie rod assembly are rotatably connected together. The intermediate rod section is threaded on the outer rod end section and a jam nut maintains this connection. A stud projects laterally outwardly from the outer rod end section for connection to a steering arm.
U.S. Pat. No. 6,406,340, which issued to Fetchko et al. on Jun. 18, 2002, describes a twin outboard motor hydraulic steering system. The steering assembly applies a force to tiller arms of twin marine outboard propulsion units and rotates the propulsion units about a steering axis between a center position and hard over positions to each side of the center position. Each propulsion unit is supported for arcuate movement about a tilt axis which is generally perpendicular to the steering axis. There is a hydraulic steering apparatus mounted on a first of the propulsion units which includes a hydraulic cylinder pivotally connected to a member which is pivotally mounted on the tiller arm of the first propulsion unit. A tie bar is pivotally connected to the steering apparatus and pivotally connected to the tiller arm of a second propulsion unit.
U.S. Pat. No. 6,561,860, which issued to Colyvas on May 13, 2003, describes a maneuvering enhancer for twin outboard motor boats. An adjustable length bar replaces a rigid bar, the one connecting the two outboards or the two outdrives of a boat, for steering purposes. The adjustable bar is electrically operated through a switch on the boat's dashboard. The switch has two operating positions, one to keep propellers creating two parallel thrusts and a second to shift the propellers to create a vee configuration by which the boats maneuverability will be enhanced.
U.S. Pat. No. 6,699,082, which issued to Zeiger on Mar. 2, 2004, describes a tie bar and mount for boat drives. The configuration connects the drives of a boat together at their centerlines so that the drives are turned at equal angles and are synchronized by the boat's steering system. The tie bar that interconnects the drives includes an end assembly that is configured to rotate 360 degrees with respect to an outer tube. The end assembly uses a lug rotatably disposed in a threaded insert to provide the rotation. An end assembly is disposed at the other end of the outer tube and provides selective length adjustment through a threaded connection between the end assembly and the outer tube. A lock nut locks the position of the end assembly. In one embodiment, the tie bar is connected to a reconfigurable motor mount that may be selectively reconfigured in left-hand, right-hand, and center configurations.
U.S. Pat. No. 6,913,497, which issued to Ahlswede et al. on Jul. 5, 2005, discloses a tandem connection system for two or more marine propulsion devices. The connection system is intended for connecting two or more marine propulsion devices together and provides a coupler that can be rotated in place, without detachment from the other components, in order to adjust the distances between the tie bar arms. In addition, the use of various clevis ends and pairs of attachment plates on the components significantly reduces the possibility of creating moments when forces and their reactions occur between the various components.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
Known tie bar systems can result in excessive stress being placed on components of the system and on certain portions of the associated marine propulsion devices when one of a pair of marine propulsion devices is tilted upwardly relative to the other. It would therefore be beneficial if a tie bar arrangement could be provided which allows sufficient freedom of movement of the components of the tie bar arrangement to avoid placing excessive stress on components of the tie bar arrangement or on the marine propulsion devices themselves.